5 numbers that explain why immigration reform is so difficult

When it comes down to it, the fight over immigration reform is really just about math.For supporters, the most important number is 218 — the number of votes it would take for the House to pass a piece of legislation.But with many House Republicans balking at a deal, the real answer may turn out to be one of the other numbers below.Here's a quick look.11.7 millionAn immigration reform activists protests at the U.S. Capitol (Getty Images)The number: That's how many …